The objective of the proposed research is to obtain basic knowledge concerning behavioral regulation of autonomic nervous system and other physiological functions by means of biofeedback and operant conditioning techniques, and to examine cognitive and physiological variables associated with learned physiological control. The first aim is to determine the degree to which various specific measures of cardiac and vascular function, and patterns of these measures, can be modified by biofeedback techniques. This research will provide a more comprehensive understanding of the cardiovascular processes associated with blood pressure regulation and of interactions between somatomotor and cardiovascular processes. The research has clinical implications for behavioral control of high blood pressure. The second aim is to continue research on the behavioral consequences of autonomic control. This research grows out of our finding that voluntary heart rate control appears to affect perception of a noxious stimulus. A number of conditions will be studied to elucidate the interaction of various cognitive physiological, and individual difference factors in this phenomenon. The research has clinical implications for the regulation of fear and anxiety. Normal volunteer subjects are studied in controlled experiments of one or more sessions. The GT-40 Computer System (PDP-11) is used to control experimental events and feedback displays, store and analyze data. Physiological measures include systolic and diastolic blood pressure (constant cuff technique), heart rate, contractile force, forearm blood flow, skin conductance, respiration, muscle tension (electromyographic activity), and finger blood flow. Questionnaires are used to assess individual differences in autonomic perception (e.g., cardiac awareness) and subjective reactions to experiments.